No-till farming (also called zero tillage or direct drilling) or cover crop farming is a way of growing crops from year to year without disturbing the soil through tillage. No-till is an agricultural technique which increases the amount of water that infiltrates into the soil and increases organic matter retention and cycling of nutrients in the soil. In many agricultural regions it can reduce or eliminate soil erosion. No-till seeding requires seeding into the previous year's crop residue and/or cover crops, which presents a number of challenges to no-till farmers.
Knife openers have become more popular than disc openers in no-till farming for several reasons. One reason is that, when using a disc to open the soil for the seed, the disc often pushes straw into the furrow where the seed is placed instead of cutting it. This is commonly referred to in the industry as “hair-pinning”. Hair-pinning is common when using disc openers because the disc needs to be set to seed shallow. However, the disc needs to be set relatively deep to cut straw instead of hair-pinning it.
Another reason why knives have become popular in no-till farming is that the knives also aerate and warm the soil by leaving a black strip for the seed to germinate in. Knives also leave a small furrow for the seed to grow in, and, therefore, the furrow protects the seedling and stays moist longer than the small groove left by a disc opener.
Knife openers can be used for depositing seed, fertilizer and other such particulate material. In some instances, fertilizer knife openers can also be used to deposit liquid or anhydrous (anhydrous ammonia) fertilizer. Generally, knife openers are comprised of a leading knife or blade, followed by a fertilizer or seed drop tube. Each of these components may need to be replaced from time to time due to wear. However, there are instances where the fertilizer/seed drop tube may see excessive wear prior to the actual knife portion of the knife assembly, in particular, when granular or particulate materials are being deposited in the soil. On the other hand, in some instances, in particular, when the soil is particularly hard and/or abrasive, the knife may see unusual wear and need to be replaced prior to replacement of the drop tube.
Currently in the industry, most drop tubes are made of a hard material, such as steel, for greater wear protection. However, because no-till seeding often starts in wetter soils, steel drop tubes get plugged with mud, thereby stopping seed or fertilizer from getting to the soil. This causes considerable down time for the seeding operation and unwanted missed strips in the field. The present applicant has observed that the use of a more flexible drop tube, such as a rubber drop tube, plugs less that steel drop tubes because the rubber tube flexes to allow the mud to dislodge and be blown out of the tube. Also, flexible drop tubes such a rubber drop tube are less expensive than steel. The disadvantage of rubber drop tubes, however, is that they can wear quicker than steel. However, if a properly designed mounting means is provided where the flexible tube can be slid down slightly and the worn tip cut off, it would make for relatively quick and cost efficient maintenance. Further, the height of the flexible drop tube would be easy to set by the grower.
There is a need in the industry for a knife assembly comprising a flexible drop tube that is easy to assemble and where the various components can be replace due to wear independently from the other components.